By Debmedia Technologies LLP · Kolkata, India · Updated
What Is an NS Lookup?
An NS lookup lists the name servers that are authoritative for a domain. These are the servers that hold the real DNS records and give the final answer when someone looks up your domain.
Knowing your name servers matters whenever you change hosting, move DNS to a new provider or troubleshoot a domain that will not resolve. The NS records tell you exactly who is in charge of the zone.
How to Use This NS Lookup
- Enter a domain such as example.com. A subdomain also works, because the tool searches upward to find the zone.
- Choose a resolver and press Lookup NS.
- Read each name server with its TTL and IPv4 or IPv6 addresses.
- Check the summary for warnings, such as a single server or a server without an address.
Reading the Results
| Column | Meaning |
|---|---|
| Name server | The host name of the authoritative server, such as ns1.example.net. |
| TTL | How long the NS record may be cached by resolvers. |
| IP addresses | The addresses where the server can be reached. |
Most domains have two to four name servers. They normally belong to your DNS host, registrar or cloud provider, which is also a quick way to learn who manages your DNS.
What a Good Name Server Setup Looks Like
- At least two servers. If one is down, the other keeps answering.
- Different networks. Servers in separate locations survive a single outage. This follows the guidance in RFC 2182, which covers selecting and operating secondary DNS servers.
- Matching data. All servers should hold the same zone version. The server-by-server health report compares their serial numbers.
- Correct delegation. The NS records at the registrar must match the ones in your DNS zone.
How to Change Name Servers
- Create the full zone, with all records, at the new DNS provider first.
- Log in to your domain registrar and replace the name servers with the new ones.
- Wait for the change to spread, which can take from minutes to a day.
- Confirm the result here, then check the world view with the global propagation tester.
Common Issues
The lookup shows old name servers
Resolvers cache NS records for as long as the TTL allows, and registry data can update slowly. Wait, then try again with another resolver.
A name server has no address
If a server in the list cannot be resolved, lookups that use it will fail. Ask your provider for the correct host names, or add glue records if the name server sits inside your own domain.
For a wider look at every record at the same time, use the multi-record viewer.
Frequently Asked Questions
Disclaimer: results come from live requests and can change as records and servers change. We cannot guarantee that every answer matches what every visitor sees.